Dishwashers



Feb. 7, 1956 J. P. FLANNERY DISHWASHERS Filed Feb. 12. 1954 INVENTOR. J mm P FLANNERY W A 77' DHNE Y United States Patent DISHWASHERS John P. Flannery, Syracuse, N. Y., assignor to Union Chemical & Materials Corp.

Application February 12, 1954, Serial No. 409,877

9 Claims. (Cl. 219-39) This invention relates to dishwashing apparatus and more particularly to impeller type dishwashers in which heated air circulation provision is made for drying the dishes.

In dishwashers of the impeller type, there is generally utilized a small quantity of detergent-laden wash water which is impelled against the dishes for washing for a period of time, following which such wash water is drained, and the dishes are rinsed with a similar quantity of preferably heated rinsing water. The heat applied to the dishes by such heated rinse water tends to dry the dishes following completion of the wash cycle and drainage of the rinse water, and it is generally the practice to provide in such washers, vents whereby air circulation from the surrounding atmosphere through the washer may take place during the drying stage. Electrical heaters have been employed for heating the washer during the drying stage, but in general, there has been lacking provision for positively circulating heated air derived from the outside atmosphere over the dishes during the drying period.

The present invention is directed to an improvement wherein provision is made for positively circulating heated air derived from outside atmosphere through the dishes during the drying period. The invention is an improvement over that generally shown in Patent 2,634,739 granted April 14, 1953. The invention more particularly has to do with introducing air for drying purposes centrally of the impeller, and distributing such air over a heating coil before circulation among the dishes, such distribution being enforced by turbine blades carried by the impeller and the continued rotation of the impeller during the drying stage.

The invention further has to do with the arrangement of an air inlet which may be concentric with the impeller shaft, so constituted as to provide a free passage for the entry of air into the dishwasher whenever the dishwasher vat has been drained of washing or rinsing fluid. The arrangement is so constructed as to lead entering air into rotating blades mounted on the inside of the impeller. Such blades being on the inside of the impeller are normally protected from contact with limited quantity of wash or rinse water, which during washing or rinsing is for the most part in circulation through the dishes.

The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being bad for this purpose to the appended claims.

In the drawings, wherein like reference characters indicate like parts:

Figure l is a vertical sectional view of the lower portion and sump of a dishwasher with the impeller mounted therein; and

Figure 2 is a transverse section taken substantially on 2,734,122 Patented Feb. 7, 1956 ice the line 2-2 of Figure 1 through the impeller showing the co-axial passageways.

Referring to the drawings, there is shown a dishwasher vat 10 having a sump 12 provided witha drain outlet 14. Such outlet is provided with a valve, as is well understood in the art, for holding wash or rinse Water within the dishwasher, or for quickly draining the liquid from the vat. Mounted on the bottom of the sump is a motor bracket 13 from which is suspended a vertical axis drive motor 16, which motor has an extended shaft 18 projecting into the tub through an enlarged aperture 20 in the bottom wall 22 of the sump 12. Surrounding the shaft in spaced relation is an upstanding sleeve 24 secured to the bottom wall 22, such sleeve providing an air passage 26 between the shaft 18 and the wall of the sleeve 24. Air may enter such passage between the motor and bracket, following the path indicated by the arrows A. On the upper end of the shaft 18 is a conical member 28 having on the exterior thereof impeller blades 30 and 32, the conical member and blades being adapted when rotating at motor speed to sweep the sump and drive the wash fluid or rinse fluid upwardly into the vat and into dishes supported thereabove.

In dishwashers of the type referred to, it is the general practice to employ a limited quantity of wash fluid, for example, two or three gallons depending upon the size of the vat, which wash fluid by reason of the impeller action, is principally maintained in circulatory motion through the dishes to effect forceful washing of the dishes by splash effect over the dish surfaces. The limited quantity of water constantly returning to the sump is immediately recirculated by the impeller, and consequently while sufficient water is used to fill the vat to the water level generally indicated at 36 when the impeller is stationary, the water level during washing scarcely exceeds the height of the lower annular lip 38 of the conical member 28. The water level 36 which would result when the impeller ceases rotation, will be seen to lie below the upper end 40 of the upstanding sleeve 24. Thus it will be seen that the quantity of wash water or rinse water employed is such that it cannot escape through the sleeve even though the impeller is not rotating.

The impeller is surrounded by a cylindrical wall screen 42 through which wash water passes on its return to the impeller for recirculation. If desired, it will be seen that the drain conduit 14 may be located outside such screen 42. Thus it will be seen that if purging of food particles caught on the screen exterior is desirable, after washing or rinsing, such action may be affected by reverse rotation of the impeller in accordance with the principle described in copending application 304,136 filed August 13, 1952.

Surrounding the screen 42 is a circular electrical heating element 44. The element may be used to boost the temperature of the rinse water if desired during the rinsing period, since it will be seen that such water in returning to the impeller will pass over the circular heater. After washing or completion of rinsing, washing and rinsing being the usual sequence of operation, the tub 10 is drained through outlet 14. Assuming that the rinsing operation is conducted with rinse water of an elevated temperature, the elimination of the rinse water through the drain will leave the dishes somewhat heated, whereby they will have a tendency to dry by evaporation of the moisture therefrom.

In order to expedite the drying action and also to assure the removal from the wash tub of super-saturated atmosphere which would tend to interfere with the drying operation, heat is applied to the vat by energization of the heating element 44 together with forced circulation of air through the vat. The conical impeller member is provided on its inside conical wall with a plurality of inwardly extending radial turbine blades 46 so that by continued rotation of the impeller in either direction, air is drawn in between the motor support bracket 13 and motor 16, and drawn up through the sleeve 24', and thereafter caused to flow forcefully radially outwardly below the lip 33 of the conical member through the screen 42 and toward the heating element 44. Such air as it passes the heating element is subjected to a temperature rise and is thereafter caused to pass upward through the dishes to enhance the drying action. It will be well understood that the vat is provided with an exhaust port to atmosphere (not shown) for such air, the port being suitably baffled to assure the prevention of the passage of wash or rinse water therethrough during the wash or rinse stages, the location of such port and the construction thereof of itself forming no particular part of the invention.

Although a single embodiment of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference willv be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In a dishwasher, a vat having a sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow and having a depending imperforate an: nular conical skirt flared at the bottom thereof, a drive shaft for said impeller projecting upwardly through the bottom of said sump, and an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller.

2. In a dishwasher, a vat having a sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow and having a depending imperforate annular skirt flared at the bottom thereof, a drive shaft for said impeller projecting upwardly through the bottom of said sump, and an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller, said conduit being concentric with said shaft and forming together with said shaft an annular passage.

3. In a dishwasher, a vat having a sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow and having a depending imperforate annular skirt, a drive shaft for said impeller projecting upwardly through the bottom of said sump, an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller, and air circulating means driven by said impeller for drawing air upwardly through said conduit, said means comprising turbine blades mounted on the inside wall of said skirt.

4. In a dishwasher, a vat having sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow and having a depending imperforate annular conical skirt flared at the bottom thereof, a drive shaft for said impeller projecting upwardly through the bottom of said sump, an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller, and air circulating means, including impeller blades mounted internally upon said impeller skirt, for drawing air upwardly through said conduit.

5. In a dishwasher, a vat having a sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow and having a depending outwardly flared annular skirt, a drive shaft for said impeller projecting upwardly through the bottom of said sump, an air inlet til conduit in the bottom of said sump extending upwardly within said hollow impeller, air circulating means disposed internally of said skirt and driven by said impeller for drawing air upwardly through said conduit, and an annular electric heating unit positioned in said sump and surrounding said impeller and adapted to heat air entering said conduit and emitted beneath the impeller skirt into the vat.

6. In a dishwasher, a vat having a sump, a vertical axis rotary impeller in said sump, said impeller being hollow and having a depending imperforate annular skirt, a drive shaft for said impeller proiecting upwardly through the bottom of said sump, an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller, air circulating means including impeller blades mounted internally upon said impeller skirt for drawing air upwardly through said conduit, and an annular electric heating unit positioned in said sump and surrounding said impeller and adapted to heat air entering said conduit and emitted beneath the impeller skirt into the vat.

7. In a dishwasher, a vat having a sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow and having a depending annular imperforate skirt flared at the bottom thereof, and constituting an air bell, a drive shaft for said impeller projecting upwardly through the bottom of said sump, an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller, said conduit being concentric with said shaft and forming together with said shaft an annular passage, air circulating means mounted internally ofsaid impeller for drawing air upwardly through said conduit and driving air radially outward into the vat from beneath said skirt, and an annular electric heating unit positioned in said sump and surrounding said impeller and adapted to heat air entering said conduit and emitted beneath the impeller skirt into the vat.

8. In a dishwasher, a vat having a sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow, closed at top and having a depending annular conical flared imperforate skirt, a drive shaft for said impeller projecting upwardly through the bottom of said sump, an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller and concentric with said shaft to provide an annular passage, air

circulating means comprising a series of blades mounted internally upon said skirt for drawing air upwardly through said conduit, and an annular electric heating unit positioned in said sump and surrounding said impeller and adapted to heat air entering said conduit and emitted beneath the impeller skirt into the vat.

9. In a dishwasher, a vat having a sump, a vertical axis rotary impeller mounted in said sump, said impeller being hollow, closed at top and having a depending annular conical flared imperforate skirt, a drive shaft for said impellerprojecting upwardly through the bottom of said sump, an air inlet conduit in the bottom of said sump extending upwardly within said hollow impeller and concentric with said shaft to provide an annular passage, air circulating means comprising a series of blades mounted internally upon said skirt for drawing air upwardly through said conduit, and an electric heating unit positioned in said sump and associated with said impeller and adapted to heat air entering said conduit.

References Cited in the file of this patent UNITED STATES PATENTS 2,422,022 Koertge June 10, 1947 

